> Date: Sun, 13 Oct 2013 16:03:26 +0200
> From: Stefan.Manegold@cwi.nl
> To: users-list@monetdb.org
> Subject: Re: Query execution time
>
> Dear all,
>
> please be aware that "time is not time".
>
> It largely depends on what you want to measure and what you can measure.
>
> Having said that, to understand why different way of measuring time result in different results,
> it's mandatory to understand what these different ways do actually measure (and why).
>
>
> 1)
> Shell built-in command "time" and unix tool "/bin/time" / "/usr/bin/time" --- beware that they are not the same! ---
> mainly measure and report the wall-clock time spent by the given command/process. See their respective man pages for details.
>
> 2)
> The time reported by mclient when using the "-i"/"--interactive" option is the time span between sending the query to the server and receiving the first part / block of the result.
>
>
> Thus, (1) includes everything from loading the mclient binary and starting the mclient process, parsing the query in mclient, sending to the server, having the server execute the query and serialize the result, sending the result back to the client, to the client receiving, parsing and rendering the result, and sending the result to /dev/null ("for free"), to a file (I/O), or to a terminal (scrolling).
>
> (2) merely includes the time the server spends on receiving and executing the query and creating the result. The abovementioned costs on the client side to receive, parse, render, etc. the result are excluded.
>
>
> Given this, and assuming you have s single query in Q.sql,
> please consider running
> time -p mclient -i Q.sql | tail -n1
> and compare the results opbtained.
>
>
> Best,
> Stefan
>
>
> ps: For more general information on running experiments and measuring time,
> please also consider studying these tutorial slides:
> https://repository.cwi.nl/noauth/search/searchrepository.php?isneditor=all&id=14302
>
>
> ----- Original Message -----
> >
> > Thanks for the link and the explication.
> > In fact I'm running the query normally first (without the time option) and I
> > get about 600ms at the end of the execution.
> >
> > Then when I use time mclient -d db query.sql/dev/null
> >
> > that gives me
> > real 1m3.895s
> > user 0m15.640s
> > sys 0m2.160s
> >
> > So it's not really the issu of cold and hot data because for the first normal
> > execution I got a time much more smaller than the second one using Time.
> >
> > I really appriciate your help because I need to get the exact real execution
> > time.
> >
> > One more question please what is the meaning of real, user and sys or where I
> > can find the difinition of these parameters.
> >
> > Thanks again
> >
> >
> > Date: Sun, 13 Oct 2013 14:36:16 +0200
> > From: martin@monetdb.org
> > To: users-list@monetdb.org
> > Subject: Re: Query execution time
> >
> > perhaps this might help
> >
> > http://www.monetdb.org/Documentation/Cookbooks/SQLrecipes/QueryTiming
> >
> > On 10/13/13 12:31 PM, baraa Mohamad wrote:
> >
> >
> >
> > That's great! Thank you very much for your appreciated help.
> >
> > I just could't really understand the output of this command.
> >
> > This is my output:
> > Real: 1m23
> > User: 0m24s
> > Sys: 0m2.3s
> >
> > I'm a little bit confused because when I execute the same query directly
> > without the time option i get 733,28ms.
> >
> > So i couldn't know what is the real execution time.
> >
> >
> >
> > Le 13 oct. 2013 à 11:29, "Martin Kersten" < Martin.Kersten@cwi.nl > a écrit :
> >
> >
> >
> >
> > How about (time mclient -d db <inputfile >/dev/null)
> >
> > On 10/13/13 11:24 AM, baraa Mohamad wrote:
> >
> >
> > Thank you for your answer.
> >
> >
> > But in general I would like to know how to get the query exexution time
> >
> >
> > without printing the results. It's for performance comparaison. I want
> >
> >
> > to evaluate MonetDB for my research and i'm working with large tables.
> >
> >
> >
> >
> >
> > Please any idea??
> >
> >
> >
> >
> >
> > Greetings,
> >
> >
> > Baraa
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Le 13 oct. 2013 à 11:02, "Martin Kersten" < Martin.Kersten@cwi.nl
> >
> >
> > < mailto:Martin.Kersten@cwi.nl >> a écrit :
> >
> >
> >
> >
> >
> >
> >
> > Hi
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > On 10/13/13 10:55 AM, baraa Mohamad wrote:
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Hello dear MontDB users,
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > I have a question please, I just need to get the query execution time
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > without showing the results of the query (for performance
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > comparaison) .
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Something which corresponds to the "traceonly" in Oracle. that will be
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > greate if I can see the query plan but for the moment the most
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > important
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > for me is to get the query execution time.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > for example: I want to know the query exection time of this query
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > (select * from source where a>10) knowing that I have more than one
> >
> >
> >
> >
> > This is not the ind of query you fire when you expect a large outcome.
> >
> >
> >
> >
> > Better use SELECT COUNT(*)....
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > hundred million records which correspond to this predicate.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Thank in advace for your appreciated help.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Baraa
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> >
> >
> >
> >
> >
> >
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> >
> >
> >
> >
> >
> >
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> >
> >
> >
> >
> >
> >
> > https://www.monetdb.org/mailman/listinfo/users-list
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> >
> >
> >
> >
> > users-list mailing list
> >
> >
> >
> >
> > users-list@monetdb.org < mailto:users-list@monetdb.org >
> >
> >
> >
> >
> > https://www.monetdb.org/mailman/listinfo/users-list
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> >
> >
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> >
> >
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> >
> >
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> >
> >
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>
> --
> | Stefan.Manegold@CWI.nl | DB Architectures (DA) |
> | www.CWI.nl/~manegold/ | Science Park 123 (L321) |
> | +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
>
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